Field of the Invention
The present disclosure relates to a developing device including a resin regulating blade.
Description of the Related Art
A developing device described in Japanese Patent Laid-Open No. 2015-34929 includes a resin developer regulating member molded from resin, and a resin developing frame member molded from resin.
The developing device includes a developing frame member, a rotatable developer carrier configured to carry a developer to develop an electrostatic latent image formed on an image bearing member, and a regulating blade as a developer regulating member configured to regulate the amount of developer carried on the developer carrier. The regulating blade is, across a direction parallel to a rotational axis of the developer carrier, arranged facing the developer carrier through a predetermined gap (hereinafter referred to as a “SB gap”) from the developer carrier. The SB gap is the minimum distance between the developer carrier and the regulating blade. The size of the SB gap is adjusted such that the amount of developer conveyed to a development area where the developer carrier faces the image bearing member is adjusted.
In association with an increase in the width of a sheet on which an image is formed, the length of the area (the maximum image area of the developing frame member) of the developing frame member corresponding to the maximum image area of an image area where an image can be formed on the image bearing member is increased in the direction parallel to the rotational axis of the developer carrier.
In a case where the developing frame member is molded from resin by injection molding, a gate portion as an inlet through which the resin flows into the molded article through a gate when the molten resin is poured into the molded article through the gate is provided at the developing frame member as the resin molded article. When a developing frame member with a great length in a longitudinal direction is molded from resin, a distance for circulating the molten resin is long, and therefore, the gate portion is typically provided in the maximum image area of the resin developing frame member such that the molten resin efficiently flows in the longitudinal direction of the developing frame member.
In a case where the developing frame member is molded from resin by injection molding, great molding pressure is on the gate portion when the molten resin flows into the gate portion through the gate, and therefore, residual stress is generated at the gate portion. The residual stress from the gate portion provided at the resin developing frame member is on the developing frame member over time, and deforms the resin developing frame member over time. As a result, in a state that the resin regulating blade is fixed to the resin developing frame member, the size of the SB gap might fluctuate over time due to the residual stress from the gate portion provided at the developing frame member.